Until I talked to Nick Bostrom, a philosopher at Oxford University, it never occurred to me that our universe might be somebody else’s hobby. I hadn’t imagined that the omniscient, omnipotent creator of the heavens and earth could be an advanced version of a guy who spends his weekends building model railroads or overseeing video-game worlds like the Sims.
But now it seems quite possible. In fact, if you accept a pretty reasonable assumption of Dr. Bostrom’s, it is almost a mathematical certainty that we are living in someone else’s computer simulation.
Dr. Bostrom assumes that technological advances could produce a computer with more processing power than all the brains in the world, and that advanced humans, or “posthumans,” could run “ancestor simulations” of their evolutionary history by creating virtual worlds inhabited by virtual people with fully developed virtual nervous systems.
Some computer experts have projected, based on trends in processing power, that we will have such a computer by the middle of this century, but it doesn’t matter for Dr. Bostrom’s argument whether it takes 50 years or 5 million years. If civilization survived long enough to reach that stage, and if the posthumans were to run lots of simulations for research purposes or entertainment, then the number of virtual ancestors they created would be vastly greater than the number of real ancestors.
For me, the possibility of simulating reality isn’t about processing power. I have little doubt that our microchips will continue to get faster and faster. But framing the issue in terms of processing power obscures the real difficulty with generating a Matrix-like hallucination of the universe: writing the code. Even if humans construct a computer capable of faking reality (i.e., it’s fast enough), I doubt we’ll ever be able to program that computer to actually run reality.
Why not? Because I think there’s an ever expanding lag between our microchips and our ability to program those microchips. Computers keep on getting faster, but we still can’t design a version of Microsoft Word that doesn’t crash. We’ve got huge mainframes that can make millions of calculations per second, and yet we have great difficulty simulating even a simple neuronal circuit.
I’m guessing that this gap exists because simulating reality, or even complex things like the cortex, requires a complete knowledge of the relevant fundamental laws. In other words, you can’t simulate a brain until you know exactly how the brain works. Otherwise your simulation will suck. So even if we have a computer of infinite power, until our knowledge is perfect, that hypothetical computer won’t be able to conjure up a pretend reality. A microchip is only as good as its code, and our codes aren’t very good.
Here, by the way, is the relevant Bostrom paper.